The study focuses on: 1. Properties of cell membrane NaK-ATPase in various psychiatric disorders, with particular reference to bipolar affective disorder. 2. The mechanism of action of chronic lithium ion administration with reference to both membrane NaK-ATPase activity and membrane phospholipids. 3. The metabolism of phosphatidic acid and phosphatidylinositols in erythrocyte membranes in different psychiatric disorders. BIBLIOGRAPHIC REFERENCES: Mabel Hokin-Neaverson, William A. Burckhardt, and James V. Jefferson. Increased erythrocyte Na ion pump and NaK-ATPase activity during lithium therapy. Res. Commun. Chem. Path. and Pharmacol. (1976) 14, 117-126. Mabel Hokin-Neaverson, David A. Spiegel, William C. Lewis, Willam A. Burckhardt and James W. Jefferson. Erythrocyte sodium pump activity in different psychiatric disorders. Res. Commun. Phsychol. Psychiat. and Behavior (1976) 1 391-403.